Known implantable sites are generally in the form of a housing including an end wall with extending side walls having free ends defining a proximal opening.
The end wall and the side walls are made of solid and rigid material, such as titanium, to ensure that the end wall and the side walls cannot be pierced by a needle. The proximal opening is closed by a substantially plane membrane of self-sealing material, thus forming a “septum”. Although the devices are generally satisfactory, they nevertheless present significant drawbacks.
Although the known devices are relatively bulky and potentially uncomfortable for the patient, the known devices provide an injection area that is small, thus exposing the surrounding tissue to risks of lesions by perforation since the probability of the practitioner piercing away from the “septum” is significant.
Furthermore, the known devices are liable to turn over under the skin as a result of movement by the patient. In extreme circumstances, the site can be turned 180°, thereby totally masking or occluding the “septum”. The device as turned over in this way becomes unusable requiring new surgery to implant a new device.
Proposals have been made to bind the site to surrounding biological tissues in an effort to keep the site from turning over. Known devices are provided with holes that enable the devices to be sutured to neighboring biological tissues.
This solution is unsatisfactory since the solution requires a relatively large surgical approach path, requires surgery that is longer and more difficult, and increases patient discomfort and the risk of infection.